I like the Philips Avent Isis. However, I had a real problem with the valve being sucked through every time and having to fish it out of the milk with my fingers. I called Philips customer service and they sent me a different type of valve which works fine. If you get one with the small, disc-shaped valve with an asterisk on it, it's no good. Make sure (if possible) you get one with the other valve, which looks more like a long plug. Honestly, if I had known about this annoying valve problem, I probably would've just got the Medela Harmony. As for all the parts of the Isis, I got used to it real quick and it doesn't bother me, but I've heard the Medela Harmony is much simpler and easier to clean.
What I like about the Isis is the massage padding. I don't know if it's that or the fact that I switched from electric to manual, but I get about 30-50% more milk using it!!!